Age Calculator
Calculate your exact age in years, months, and days from your date of birth
How the Age Calculator Works
Our age calculator uses calendar-accurate math to determine your exact age in years, months, and days. Unlike simple calculators that divide by average days, we account for the actual number of days in each month and leap years.
1
Enter your date of birth
Pick your birth date to compute exact years, months, and days.
2
Choose an “as-of” date
Use today, or set any date to calculate age on a specific day.
What you’ll get
- Exact age: Years, months, and days since birth
- Birth weekday: The day of the week you were born
- Next birthday: Countdown to your upcoming birthday
- Total time lived: Days, weeks, hours, and minutes
Tip: If you’re seeing a one-day difference vs another calculator, it’s usually because of timezones and whether the tool uses date-only math.
Common Use Cases
Calculate age for official documents
Verify eligibility for age-restricted services
Plan birthday celebrations
Calculate age differences between people
Determine retirement eligibility
Frequently Asked Questions
How is age calculated exactly?▼
Age is calculated using calendar-accurate math. We count complete years, then remaining months, then remaining days. This accounts for varying month lengths and leap years correctly.
Why might my age differ by one day on different calculators?▼
This usually happens due to timezone differences. Our calculator uses date-only math (no time component) to ensure consistent results regardless of your timezone.
How do you handle February 29 birthdays?▼
For people born on February 29 (leap day), we calculate their birthday as February 28 in non-leap years. This is the most common convention used worldwide.
Can I calculate my age on a future date?▼
Yes. Set a custom "As of" date to calculate how old you will be on any future date.
Does this store my date of birth?▼
No. All calculations happen in your browser. We do not store, transmit, or save your personal information.
About Accuracy
Our calculator handles the most common edge cases correctly, and aims to avoid “off by one day” errors.
- Leap years: February 29 birthdays are handled correctly, with non-leap years defaulting to February 28.
- Month lengths: Different month lengths (28–31 days) are accounted for.
- Timezone safety: We use date-only math to avoid timezone related shifts.